Spectrophotometric evaluation of color errors generated in the visual color duplication procedure for current ceramic veneers

Abstract

Background/purpose: Color errors associated with the visual color duplication approach for ceramic laminate veneers are still challenging in esthetic dentistry. The aim of this study is to evaluate color errors generated during traditional visual shade matching approach.

Materials and methods: Eighteen stooth-shaped veneer discs (shade A2 and 0.7 mm in thickness) were fabricated using six veneer materials. The veneer specimens placed on five extracted teeth with nominal shade A2 formed veneer-tooth combinations. Color coordinates of the A2 shade tab, the extracted teeth, and the veneer-tooth combinations were measured using a spectrophotometer. Then, the veneers were reduced to 0.5 mm, and 0.3 mm in thickness consecutively. Color measurements were performed repeatedly. Color differences of the extracted teeth to veneer-tooth combinations (ΔEt-v), veneer-tooth combinations to shade tab (ΔEv-s), and translucency parameter (TP) values were calculated and analyzed using Two-way ANOVA.

Results: ΔEt-v ranged from 2.0937 to 5.0603 (mean of 3.1833±1.5485). Mean of ΔEv-s was 4.0103±1.8508. ΔEt-v and ΔEv-s values were significantly influenced by veneer material and thickness (P<0.05). TP values decreased gradually with the lessening of veneers thickness.

Conclusion: Acceptable color duplication of ceramic veneers cannot be achieved by routine visual shade replica protocols, when the thickness of veneers is less than 0.7 mm. Specified color matching standards for the ceramic veneers are needed.

Keywords: Ceramics; Color; Dental veneers; Tooth.

Figure 1

Veneer specimens, extracted teeth and PR655. (a) Veneer specimens; (b) extracted teeth; (c) PR-655 Spectra Scan.

Figure 2

Linear regression analysis of relationship between values of ΔE_t-s∗ and ΔE_t-v∗. ΔE_t-s: color difference between the tooth and the shade tabs. ΔE_t-v: color difference between the tooth and the veneers. (a),(b),(c),(d),(e),(f): Relationship between values of ΔE_t-s and ΔE_t-v for IPS e.max LT, IPS e.max HT, Vita Enamic, Vita Mark II, 3M Ultimate, and Vita Sprinity group, respectively.

Figure 3

Color difference of veneer to shade tab (ΔE_v-s∗). EMHT: IPS e.max HT; EMLT: IPS e.max LT; VE: Vita Enamic; VM: Vita Mark II; MU: 3M Ultimate; VS: Vita Sprinity. ΔE/ΔE_v-s: Color difference between veneer and shade tab. (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)

Figure 4

Translucency parameter (TP) of different ceramic materials and thicknesses. EMLT: IPS e.max LT; EMHT: IPS e.max HT; VE: Vita Enamic; VM: Vita Mark II; MU: 3M Ultimate; VS: Vita Sprinity. TP: Translucency parameter.